Automatic telephone switch



Aug. 12 1924. 1,504,227

E. w. GENT AUTOMAT I C TELEPHONE SWITCH Filed Ma 17, 1921 9 War/{602:

Patented a... 12, 1924.

UNITED STATES PATENT OFFICE.

EDGAR WALTER GENT, OF HORRISTOWN, NEW JERSEY, ASSIGNOR TO- -WESTEBN ELEC- TRIO COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

I AUTOMATIC TELEPHONE SWITCH.

Application filed Kay 17, 1921.

To all whom it may concern:

Be it known that I, EDGAR W. GENT, a citizen of the United States residin at Morristown, in the county of Morris, tate of New Jerse have invented certain new and useful mprovements in Automatic Telephone Switches, of which the following is a full, clear, concise, and exact description.

This invention relates to automatic selector and connector switches for use in automatic telephone systems for interconnecting subscribers lines. More particularly, it re a tee to two motion switches, that is,

switches in which contact brushes are moved 1 first in one direction to select a group of stationary terminals, and then in another direction to select a set of terminals in the selected group. It further relates to a switch of the above character in which a single motor magnet is adapted to move the contact brushes through both selective movements.

The object of the invention is the provision of a simple, durable and economical switch structure of the above character in which a minimum number of magnets are em loyed.

he principal feature of the invention consists in the provision of a simple, mechanical locking device which operates antomatically upon the completion of each group selecting movement of the contact brushes to efi'ect a change in the direction of movement of the brushes, whereby they are caused to move over the terminals in the selected group until. a desired set of terminals is reached. The-mechanical locking device comprises an inertia retarded plunger, which on account of its sluggishness in operation is ineffective during the group selecting movement of the switch, but effective immediately after the switch comes to rest following group selection.

In the preferred form the switch comprises a bank of stationary contact terminals consisting ofa number of groups, usually ten, and each group consisting usually of ten sets of terminals. The several groups are arranged in arcuate, concentric rows, that is, each arcuate row is synonymous with a group.

Contact brushes for cooperating with the bank terminals are mounted on a longitu- Serial No. 470,385..

plunger, normally stands ina vertical position with its lower end restin on the brush carrying bar. A row of etents, corresponding in number with the groups or 'arcuate rows of stationary terminals, is provided on the brush carrying 'bar, and the end of the locking plunger is adapted to drop into any of these detents when they are moved into alignment therewith and the bar is brought to rest for a period of time sufiicient t permit the locking plunger to drop far enough to engage the detent. As previously stated, the locking plun er normally rests on the brush carrying ar,-but it does not normally engage any of the detents. During group selection the bar is moved longitudinally, and except in the case of a selection in the first group, one or more of the detents is moved past the end of the locking plunger. This movement is efi'ec-ted so rapidly that the detents pass the locking plunger before it can drop far enough to engage one of them. Between each detent there is a. tooth-like portion forming part of the bar, and each of these tooth-like portions is provided with a beveled end which engages the lower end of the locking plunger in passing, and restores it to its normal position. In other words, the .beveled tooth acts as a compensator to maintain the locking plunger in its normal position during group selection.

If, for example, a set 011 terminals in the eighth group is to be selected, seven detents on the bar will move past the end of the locking plunger and the eighth detent will be situated in alignment with the plunger when the group selecting movement ceases. The locking plunger W111 then drop into the eighth detent and lock the bar against further longitudinal movement.

During group selection, the carriage on which the bar is mounted is prevented from rotating by a spring latch, but upon the motor magnet being again energized after the bar is looked, as above described, the carriage is forced out of engagement with the spring latch, and rotated until the brushes engage a desired set of terminals.

For a more complete description of the switch and its operation, reference will now be made to the accompanying drawings in which Fig. 1 is a plan view of the switch partly in section;

Fig. 2 is an elevational view of the switch;

Fig. 3 is a detail view illustrating the operation of the locking plunger;

Fig. 4 is a plan view of the locking plunger and associated parts; and

Fig. 5 is a. detail view of one set of contact brushes.

The plate 1 is molded of a suitable insulating material, and has the contact terminals 2, 3 and 4 embedded therein. The terminals 2 are test contacts, and the terminals 3 and 4 are talking circuit contacts. The test terminals 2 are situated opposite the terminals 3 and 4 as a matter of convenience. and 4 could all be grou ed together instead of being arranged as s own in Fig. 2. It will be understood that one test terminal 2 is associated with each pair of talking terminals 3 and 4, and that when the brush 8 makes contact with a test terminal, the brushes 9 and 10 simultaneously make contact with the talking terminals 3 and 4 associated with that articular test terminal.

The contact brus es 8, 9 and 10 are insulatively mounted on the bar 5, and the latter is slidably mounted in bearings 6 and 7, which are integral with the rotatable carriage 30. The carriage 30 is mounted on the bushing 15, as is best shown in Fig. 1, and is adapted to rotate thereabout. A boss 31 on the carriage 30 is normally engaged by the latch spring 32, and carriage 30 isv thereby restrained from rotating during group selection. This will be more clearly explained hereinafter.

The bushing 15 is of non-magnetic material. It extends through the solenoid 21, and is bored out to receive the solenoid plunger 20.

The pinion 14, ratchet 16 and crown-tooth ratchet 17 are integral and are rotatably mounted on bushin 15. The helical spring 38, one end of whic is secured to the molded plate 1, and the other end to pinion 14 is provided for restoring the switch to norma Spring 22 is the restoring spring for the solenoid plunger 20, and normally holds the latter in the position shown in Fig. 1.

If desired, the terminals 2, 3

An elliptical aperture 23 is provided in the bushing 15, and a pin 24 carried by the solenoid plunger 20 engages aperture 23. Upon energization of solenoid 21. the plunger 20 is pulled up against the tension of spring 22, and is at the same time rotated t rough a small angle by reason of the engagement of pin 24 with the aperture 23.

A crown-tooth ratchet 25 is secured to the solenoid plunger, and is adapted upon each operation of the latter to engage the crown-tooth ratchet 17 and rotate it together with ratchet 16 and pinion 14 through an angle corresponding with the pitch of the teeth of ratchets 16, 17 and 25.

The bar 5 is rovided with rack teeth 13 on one edge. hese are engaged by pinion 14, and the rotation of the latter will move the bar 5 longitudinally, together with brushes 8, 9 and 10 when the bar is not locked against longitudinal movement.

The locking plunger 26 is vertically and slidably mounted in the bracket 27 and is provided with a disc 28 which fits rather loosely in the cup 29. The disc 28 and cup 29 form a dash pot which retards longitudinal movement of the locking plunger.

The bar 5 is provided with a series of detents 12, corresponding in number with the groups or arcuate rows of bank terminals.

The switch operates in response to impulses of current through the solenoid 21. These impulses are very rapid, usually at the rate of about ten per second, and it follows that during the longitudinal movement of the bar 5, the detents 12 will pass the end of the locking plunger 26 at the rate of about ten per second. The locking plun er cannot dro fast enough to engage the etents when t ey are passing at such a rate. It does drop to some extent, however, during the passing of the detents, and is restored to its normal position by the beveled ends of the teeth 11, which engage and force it back in passing.

When the group selecting impulses are completed. the longitudinal movement of bar 5 is discontinued and during the interval between the group selecting and terminal selecting impulses, the locking plunger drops into the detents corresponding to the selected group. In Fig. 3 the locking plunger is shown engaged with the second detent.

In response to the first impulse of the second series, the boss 31 is pulled away from the latch spring 32, and the carriage 30 together with bar 5 and brushes 8, 9 and 10 are rotated one step, and for each succeedin impulse they are rotated one ste until t e desired set of terminals is reache Durin the entire selecting operation of the SWltfil, holding pawl 18 is engaged with ratchet 16 and remains in engagement therewith until it is desired to restore the switch to normal. Pawl 18 is provided with a tailpiece 18' which serves as an armature for releasing magnet 19, and u on energization of the latter, awl 18 is wit drawn from enga ement wit ratchet 16.

he lockin plun er is released from enga ement wit the detent 12 by means of a el crank 34 having a horizontal arm which on ages the under side of the head of the lociing plunger, and a vertical arm which1s enga ed by a hook 37 carried by pawl 18. The ell crank'34 is pivoted at 35, and is normally retracted by spring 36. Fig. 3 shows the relation between the vertical arm of the bell crank 34, and the hook 37 with the switch in an ofi-normal position, and in the act of restoring. The pawl 18 in Fi 3 has been pulled out of engagement wit ratchet 16, and the carriage 1s rotating due to the energy stored in spring 38 in the direction'indicated by the arrow. The dot and dash line in Fig. 3 indicates the path of the end of the vertical arm of bell crank 34, and-it will be seen that the vertical arm will be engaged by the hook 37, just prior to completion of the rotary restoring movement.

The bell crank 34 will be thereby rotated, and the horizontal arm will lift the locking plunger out of the detent. The bar 5 will then move longitudinally to its normal resting position as shown in Fig. 2, and the release magnet 19 will thereafter be deenergized.

Springs 39 and 40 provide self-interrupting contacts for use when the switch is emloyed as a selector, when, as in other wellown two motion selector switches, the second motion continues until a set of terminals connected with an idle trunk is found.

What is claimed is:

1. An automatic switch comprising stationary contacts arranged in groups, a movable contact member, a single motor mechanism for moving said contact member first in one direction to select a group and then in another direction to select a contact in the selected group and mechanical means for automatically effecting thechange in girection of movement of said contact mem- 2. An automatic switch comprising stationary contacts arranged in groups, a movable contact member, a single motor mechanism for movin said contact member first in one directio to select a group and then in another direction to select a contact in the selected oup and an inertia device operable to e ect the change in direction of said contact member.

3. An automatic switch comprising stationary contacts arranged ingroups, a movable contact carrying member having .detents, a single motor mechanism for moving said contact carrying member, first in one direction to select a group and then in a second direction to select a contact in the selected group, and an inertia device arranged to co-operate with the detents on said contact carryin member, said inertia device bemg mcapab e of engaging an of said detents during the movement 0 said contact carrying member in the first direction and capable of engaging one of said detents after a substantial pause in the movement of said contact carrying member following a movement thereof in the first direction, said engagement being effective to change the direction of movement of said contact carrying member.

4. An automatic switch comprising statlonary contacts arranged in concentric rows, a movable contact member, a single motor mechanism for moving said contact member first in one direction to select a row and then circumferentially to select a contact in the selected-row and an inertia device operable to effect the change in direction of said contact member.

5. An automatic switch comprising stationary contacts arranged in concentric rows, a movable contact carrying member, and a contact therefor, a solenoid, a plunger for said solenoid adapted to reciprocate in response to current impulses through said solenoid, a ratchet adapted to be driven step by step by said plunger, and means cooperating with said ratchet to im art motion to said contact carrying mem r first in one direction to select a row of stationary contacts and then in another direction to select a contact in the selected row.

6. An automatic switch comprising a plurality of concentric rows of stationary contacts, a rotatable brush carriage, a longitudinally movable bar mounted on said carriage, a contact brush mounted on said bar, a single motor mechanism for movin said bar longitudinally together with sai contact brush to select a row of stationary contacts and for rotating said carriage together with said bar and contact brush to select a contact in the selected row.

7. An automatic switch comprising a plurality of concentric rows of'stationary contacts, a rotatable brush carriage, a lOIlgltudinally movable bar mounted on said carriage, a contact brush carried by said bar, a common motor means for moving said bar longitudinally and for rotating said carriage together with said bar, and contact brush, means for preventing the rotation of said carriage by said motor means while said bar is free to move longitudinally, and an inertia device operable to engage said bar after it has moved from its-normal position and-stopped at a selected row of stationary contacts to prevent further longitudinal movement of said bar until the switch is released for return tonormal.

8. In an automatic switch, a plurality of concentric rows of stationary contacts, a bar, a contact brush carried by said bar for co-operating with said stationary contacts, said bar movable longitudinally to position said contact brush in operable relation to a selected row of stationary contacts and rotatable to select a contact in the selected row and an inertia device operable to engage said bar to prevent longitudinal movement thereof during the rotary selective movement, and driving means for said bar.

9. In an automatic switch, stationary contacts arranged in groups, a bar, a contact brush on said bar, a plurality of beveled teeth on said bar, detents between said teeth, a plunger normally resting on said bar but out of engagement with said detents, driving means for moving said bar longitudinally to select a group of stationary contacts, said plunger being adapted to ride over said detents during the longitudinal movement of said bar, by reason of its inertia, the beveled teeth being adapted to engage said plunger during the longitudinal movement of said bar and to return said plunger to its normal position, said plunger being adapted to drop into a detent corresponding with a selected group of stationary contacts when said bar is stopped following its longitudinal selective movement thereby locking said bar against further longitudinal movement, said driving means being further adapted to rotate said bar, after the latter is locked, to select a contact in the selected group. 10. An automatic switch comprising a rotatable unit, means to exert a restraining force a ainst rotation on said rotatable unit, a longltudinall movable brush carriage mounted on sai unit, a source of power for moving said brush carriage, an inertia device mounted on said rotatable unit, and means including said inertia device for locking said brush carriage to said rotatable unit whereby Lpower applied to said brush carrlage w1 unit to overcome said restraining force.

11. An automatic switch comprising a solenoid, a lunger for said solenoid a cam for translatln a longitudinal movement of said plunger into a rotary motion, a clutch member secured to said plunger. a cooperating clutch member rotatably mounted on said plunger, a pinion secured to said 0000- erating clutch member. a longitudinally movable brush carriage having a rack cooperating with said pinion and an inertia device for locking said brush carriage and said pinion together whereby the longitudinal movement of said carriage is changed to a rotary movement corresponding to the movement of said pinion.

In witness whereof, I hereunto subscribe my name this 13th day of May, A. D. 1921.

EDGAR WALTER GENT.

be transmitted to said rotatable 

